Osteoarthritis (OA) is a progressive form of arthritis that causes pain and stiffness in the joints. Experts often break it down into five stages based on the symptoms a person presents with.

Doctors often use what is known as the Kellgren-Lawrence (KL) classification system to describe OA.

The stages range from stage 0 to stage 4. Each stage has an association with worsening symptoms as the condition progresses.

This article reviews the five stages of KL classification for OA, whether a person can slow the progression of OA, treatment, and more.

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OA is the most common type of arthritis and can lead to disability in some people.

Pre-OA is a current topic of study. Researchers hope to identify potentially reversible biomarkers and changes that may indicate the onset of OA.

Identifying the signs of OA before it develops into a clinical condition may help prevent some cases from developing.

Healthcare professionals may assign stage 0 to people with healthy joints.

Learn about osteoarthritis.

Stage 1 OA is the earliest stage of active disease. At this stage, healthcare professionals cannot see any damage to the joint on an X-ray.

A person may develop small bony spurs known as osteophytes.

Often, a person will not have any damage to the joint, but the cartilage may show slight damage. Another potential sign at this stage is a narrowing of the space between the bones.

At the early stage, a person may not develop any noticeable symptoms. A healthcare professional may recommend nonpharmaceutical interventions at this stage that can include:

  • weight loss or management
  • avoiding certain activities, such as those that put extra burden on the affected joint
  • exercise to improve strength
  • occupational therapy, which may include fitting for braces and other assistive devices

Learn about early symptoms of OA.

At stage 2, a person may start to notice pain and stiffness in the affected joints. The symptoms may become more noticeable after a long period of rest, such as in the morning or after sitting for long hours.

An X-ray may reveal osteophytes as well as a narrowing of the joint and slight bone damage. At this stage, the affected joints may start to thicken and harden. A new layer of bone can also develop under the cartilage.

The joint will generally still function normally with no rubbing or grating.

If pain develops, a doctor may recommend either nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen as an initial pharmaceutical treatment at this stage.

Read more about mild OA.

At stage 3 OA, symptoms continue to worsen. A person may notice pain during activity along with increased pain and stiffness following periods of rest.

They may also notice swelling in the affected joint.

Imaging tests, such as X-rays, will show a narrow space between the bones in the joint, deformity to the ends of the bone, and some damage to the cartilage. Bony spurs will show growth.

Healthcare professionals may recommend injections around the joint for severe pain. However, glucocorticoid injections are not always effective, and hyaluronic acid injections may not be any more effective than placebos, according to studies.

Stage 4 OA is the most severe level of the condition.

Symptoms can include:

  • inflammation that does not go away
  • increased pain with movement
  • joint stiffness
  • increased friction in the affected joint
  • decrease in protective fluid in the joint

When viewed on an X-ray or other imaging test, healthcare professionals will typically see:

  • significant damage to the cartilage
  • large bone spurs
  • deformity at the ends of the bones that connect at the joint
  • ends of bones rubbing and grinding against each other

Treatments at this stage can vary according to preferences and responses to previous interventions. People who do not respond well to previous interventions may benefit from surgery.

People who do not want surgery or who are not good candidates may benefit from stronger pain relievers, such as opioids.

Read more about severe OA.

Currently, treatments can only help manage the symptoms of OA.

However, researchers are getting closer to understanding the underlying mechanisms of OA. In a 2020 article, the author outlined the underlying mechanics behind the development of OA. They indicated that future treatments may be able to target specific aspects in relation to the development of the condition and potentially help reverse the damage.

The article mentions the use of stem cells as a potential avenue for future treatment. While generally positive, a 2018 review of studies notes that much of the supporting evidence is low quality, has limited sample sizes, and may not be reproducible.

For now, experts generally recommend against using stem cells for OA.

Treatments for OA can include a combination of lifestyle changes as well as pharmaceutical and nonpharmaceutical treatments. These can also change on the basis of the stage and severity of symptoms.

In the early stages before symptoms become severe, making lifestyle changes, such as managing weight or losing excessive weight, can help.

Healthcare professionals may also recommend the use of braces or other assistive devices to help lessen the use of affected joints.

For pain, most doctors recommend the use of NSAIDs or acetaminophen. A person should discuss long-term use with a healthcare professional due to the potential side effects of each type of medication.

Some people may benefit from occupational or physical therapy.

As OA worsens, doctors may recommend stronger pain relief or surgical correction of the joint.

Learn more about treatment for OA.

The following sections provide answers to some frequently asked questions about OA.

What is life expectancy with osteoarthritis?

Evidence suggests that people with OA typically live for an average of 30 years past diagnosis. However, several factors can affect life expectancy. A person should discuss their situation with a healthcare professional, who can assess their overall health.

How quickly does osteoarthritis progress?

OA generally develops slowly over time. The amount of time it takes to progress varies between people. Taking active steps to protect the joints and following a doctor’s advice on treatment may help.

OA breaks down into four active stages and one pre-OA stage. Experts have categorized the stages on the basis of the symptoms and how the affected joints look.

Treatments can involve changes in lifestyle, such as taking steps to manage weight, as well as medical interventions such as medications, surgery, braces, and occupational or physical therapy.